Sodium Hydroxide → HCID 10178874, compound

Participants

Reaction Steps

0.769 mg (1.658 mmol) of N-tert-butoxycarbonyl-3-(4-alloxycarbonyl-2-aminophenyl-thio)-L-alanine methyl ester was dissolved in 40 ml TBME and emulsified in 220 ml 0.1M sodium chloride solution; 3 mM sodium phosphate buffer pH 7.5 under vigorous stirring. 1.0 ml Alcalase 2.4 L [a subtilisin Carlsberg from Novo Nordisk] was added and the pH maintained at 7.5 under vigorous stirring by the controlled addition (pH-static) of 1.0N sodium hydroxide solution. After 45.4 h 23.6 ml of 1.0N sodium hydroxide solution was consumed and the conversion degree was >97% (HPLC analysis). The reaction mixture was extracted with 100 ml TBME. After phase separation, the aqueous phase was acidified to pH 2.3 with 32% hydrochloric acid and extracted with 3×250 ml ethyl acetate. In case a stabile emulsion was formed the phase separation was achieved by filtration on Dicalite. The combined ethyl acetate extracts were dried on anhydrous sodium sulfate and evaporated. The residue was dissolved in dichloromethane, evaporated and dried at HV to give 604 mg N-tert-butoxycarbonyl-3-(4-alloxycarbonyl-2-aminophenylthio)-L-alanine as a pale yellow solid (yield: 93.9%, purity: 95%).

Provenance & Evidence